// TODO: must be verified
public decimal ToDecimal()
{
var scaleDivisor = BigMath.Pow(BigInteger.FromInt64(10), _scale);
var remainder = BigMath.Remainder(GetUnscaledValue(), scaleDivisor);
var scaledValue = GetUnscaledValue() / scaleDivisor;
var leftOfDecimal = (decimal)scaledValue;
var rightOfDecimal = (remainder) / ((decimal)scaleDivisor);
return(leftOfDecimal + rightOfDecimal);
}
/**
* Multiplies a number by a power of five.
* This method is used in {@code BigDecimal} class.
* @param val the number to be multiplied
* @param exp a positive {@code int} exponent
* @return {@code val * 5<sup>exp</sup>}
*/
public static BigInteger MultiplyByFivePow(BigInteger val, int exp)
{
// PRE: exp >= 0
if (exp < FivePows.Length)
{
return(MultiplyByPositiveInt(val, FivePows[exp]));
}
else if (exp < BigFivePows.Length)
{
return(val * BigFivePows[exp]);
}
else // Large powers of five
{
return(val * BigMath.Pow(BigFivePows[1], exp));
}
}
public static BigDecimal Pow(BigDecimal number, int n)
{
if (n == 0)
{
return(BigDecimal.One);
}
if ((n < 0) || (n > 999999999))
{
// math.07=Invalid Operation
throw new ArithmeticException(Messages.math07); //$NON-NLS-1$
}
long newScale = number.Scale * (long)n;
// Let be: this = [u,s] so: this^n = [u^n, s*n]
return((number.IsZero)
? BigDecimal.GetZeroScaledBy(newScale)
: new BigDecimal(BigMath.Pow(number.UnscaledValue, n), BigDecimal.ToIntScale(newScale)));
}
public BigIntegerTest()
{
twoToTheSeventy = BigMath.Pow(two, 70);
SetUp();
}
public void PowI()
{
Assert.True(BigMath.Pow(two, 10).Equals(twoToTheTen), "Incorrect exponent returned for 2**10");
Assert.True((BigMath.Pow(two, 30) * BigMath.Pow(two, 40)).Equals(twoToTheSeventy), "Incorrect exponent returned for 2**70");
Assert.True(BigMath.Pow(ten, 50).Equals(aZillion), "Incorrect exponent returned for 10**50");
}
/**
* It calculates a power of ten, which exponent could be out of 32-bit range.
* Note that internally this method will be used in the worst case with
* an exponent equals to: {@code Integer.MAX_VALUE - Integer.MIN_VALUE}.
* @param exp the exponent of power of ten, it must be positive.
* @return a {@code BigInteger} with value {@code 10<sup>exp</sup>}.
*/
public static BigInteger PowerOf10(long exp)
{
// PRE: exp >= 0
int intExp = (int)exp;
// "SMALL POWERS"
if (exp < BigTenPows.Length)
{
// The largest power that fit in 'long' type
return(BigTenPows[intExp]);
}
else if (exp <= 50)
{
// To calculate: 10^exp
return(BigMath.Pow(BigInteger.Ten, intExp));
}
else if (exp <= 1000)
{
// To calculate: 5^exp * 2^exp
return(BigMath.Pow(BigFivePows[1], intExp) << intExp);
}
// "LARGE POWERS"
/*
* To check if there is free memory to allocate a BigInteger of the
* estimated size, measured in bytes: 1 + [exp / log10(2)]
*/
var byteArraySize = 1 + (exp / 2.4082399653118496);
//if (byteArraySize > System.Diagnostics.Process.GetCurrentProcess().PeakVirtualMemorySize64) {
// // math.01=power of ten too big
// throw new ArithmeticException(Messages.math01); //$NON-NLS-1$
//}
// More than 128Mb
if (byteArraySize > (128 * 1024))
{
throw new ArithmeticException(Messages.math01);
}
if (exp <= Int32.MaxValue)
{
// To calculate: 5^exp * 2^exp
return(BigMath.Pow(BigFivePows[1], intExp) << intExp);
}
/*
* "HUGE POWERS"
*
* This branch probably won't be executed since the power of ten is too
* big.
*/
// To calculate: 5^exp
BigInteger powerOfFive = BigMath.Pow(BigFivePows[1], Int32.MaxValue);
BigInteger res = powerOfFive;
long longExp = exp - Int32.MaxValue;
intExp = (int)(exp % Int32.MaxValue);
while (longExp > Int32.MaxValue)
{
res = res * powerOfFive;
longExp -= Int32.MaxValue;
}
res = res * BigMath.Pow(BigFivePows[1], intExp);
// To calculate: 5^exp << exp
res = res << Int32.MaxValue;
longExp = exp - Int32.MaxValue;
while (longExp > Int32.MaxValue)
{
res = res << Int32.MaxValue;
longExp -= Int32.MaxValue;
}
res = res << intExp;
return(res);
}
